The patentable subject matter is eye microsurgery method of the transplanted cornea attachment and the implant used for attaching transplanted corneas, both donor corneas and artificial corneas, without using sutures used.
The cornea is the front transparent part of the eyeball characterised by a larger curvature. The thinnest part of the cornea is in its centre, where its average thickness ranges from 500-600 μm. Various pathologies may lead to corneal dysfunction necessitating corneal transplantation-replacement of the old damaged tissue with new donor or artificial tissue.
There are three basic types of corneal transplantations. Full thickness transplants (penetrating), front layers transplants (anterior lamellar keratoplasty) and posterior layers transplants (posterior lamellar keratoplasty). Only the last type of the transplants allows donor tissue to be attached without using sutures.
Both anterior lamellar and penetrating keratoplasty require tight suturing of the transplant cornea to the recipient's tissue. Such methods involve manual suturing making them time-consuming and less precise. The post-procedural corneal shape is irregular with high postoperative astigmatism. Sutures that are too loose may result in insufficient wound tightness, risk of infection-related complications and inflammation and, in effect, transplant rejection. On the other hand, too tight stitching results in postoperative disturbances of the corneal shape.
During corneal transplantation (keratoplasty) the donor and recipient tissues are cut in such a way so that they fit with each other. This is done by means of various types of trephines-circular cutting devices having various diameters which are usually disposable. The cutting of the tissue is accomplished by a circular motion. Therefore, trephines can only be used for round transplants. The technical complexity of this procedure results in the donor and recipient tissues not being ideally matched, which has a negative influence on the final result of keratoplasty.
In the recent years, development of laser technology, in particular development of femtosecond laser for corneal surgery, has created new possibilities, also in the field of corneal transplantation. The femtosecond laser is capable of making incisions in any given plane of the cornea with precision of several micrometers. This allows the donor and recipient tissues to be fitted much more precisely. Different modifications of the transplant shape were also proposed to obtain the lowest possible postoperative astigmatism.
Unfortunately, the advantages of using femtosecond lasers in keratoplasty are so far limited by the necessity to put in sutures causing substantial astigmatism which is hard to predict as well as leading to the complications as mentioned above.